Does wheel weight make a difference?

[YeeFit]

I figured I'd ask the more rev happy ppl in this forum to see if they have any insight on wheel weights and how they affect our cars.

I understand that the current Fit Sport rims weigh 15.8lbs roughly.. now I have been contemplating getting 17" wheels that weigh 18lbs. I know that isn't much of a difference, but the wheels I am also considering are a set of 15" 10.6lb wheels.

So the difference in weight between the 2 different wheels that I am considering is 7.4lbs.

Now this could be a pretty big number when it comes to how my Fit will perform seeing as we are just rated above 100hp...

Can someone fill me in with their knowledge? what are the advantages and disadvantages?

I'm not going to track my car, but I do like to drive aggressively and don't want to make my Fit any slower than it already is.

[s0x]

well look at it like this you lose 5.2 lbs on each wheel and youll end up losing lets say 1 lb on each tire (thats probably completely wrong but if you buy a set of low pros your gunna lose weight so now youve lost 25 lbs off your car every little bit adds up....so you do that then you get a carbon hood loose a few lbs with an aftermarket intake now you lost like 40 lbs on a car that only weighs 2400 lbs weight adds up quick now if you had a camero who effin cares lol i would say go for the 15s makes more sence to me :P but im a noob so doesnt matter what i think

[George02]

nah through some 28's on it haha jk yes it makes a difference. my car loves the new wheels

[Gil554]

Having not tracked my Fit yet, I can't speak to it effect of lowered un-sprung weight. In previous cars I've owned, lowered un-sprung weight didn’t seem to make a big difference. With a low powered car such as ours, lighter wheels and tires will improve driving characteristics to a certain extent for street driving.

The track is a different story. When you are trying to take a car to it's limit, lowering weight can make dramatic differences. Seeing as you don’t plan on tracking your car, I doubt you'll notice much, except for being slower if you pop on some big shoes.

I am sure someone here can better speak to the greater impact of lowered un-sprung weight versus just lowered weight. I remember reading the impact of lowered un-sprung weight was 2 or 3 to 1 versus overall weight loss (carbon hood).

[j5ive]

Weight you save on wheels makes a lot more difference on the driving experience than the weight you save on the rest of the car; It's moment of inertia. The heavier a wheel is (18lbs vs 10lbs) , the more force is required to get it spinning. Also, the further out the mass is from the rotational center (17" vs 15") , the more force is required to get it moving. So you can see how lighter wheels will make a difference when you accelerate or turn. But the same also applies when you're trying to slow down. The lighter the wheel (rotating mass), the less force is required to bring it to a stop. Now times that effect on all 4 wheels, and we're talking a big difference here. And because it takes less force to spin the wheels, there's also some fuel economy that can be gained with lighter wheels (steelies vs alloys for example).

My previous B5 Audi A4 1.8t for example, I can run 15.5 quarter mile times at the track with OEM 15" alloys. But with my 18" Mille Miglia Spyders on, my 1/4 mile time increased significantly to high 17 seconds. Ask anyone who drag races. That is a huge amount of difference.

Hope this helps.

[YeeFit]

That does make a lot of sense.. thank you.

I would prefer to opt for better gas mileage, accel, braking and handling then going for the look of a 17" wheel.

[tricolor]

Weight you save on wheels makes a lot more difference on the driving experience than the weight you save on the rest of the car; It's moment of inertia. The heavier a wheel is (18lbs vs 10lbs) , the more force is required to get it spinning. Also, the further out the mass is from the rotational center (17" vs 15") , the more force is required to get it moving.

Very well explained! And I can actually feel the effect of lighter wheels now that I drive with my summer shoes (lighter rims & tires). The difference is actually more noticable than with my AirBox or my CatBack exhaust mods... no kidding!

[YeeFit]

I think I am sold on the lighter 15" wheels over the 17s.. thanks a bunch guys. made my decision a lot easier!

[George02]

my 16's are lighter than my stocks. but 15's are cool might buy some later down the road?

[Bap]

I have heard from some where that every 4 pounds of rotating mass you gane or loss is ruffly equivlent to 1 horse power gained or lost through the drive train. so what ever weight svaings or pound packing wheels you put on the car the 4/1 ratio only appleys to the drive wheels and the rest adds or sutracts to the cars weight. so if you free up about 12 pounds off your wheels you might gain about three hps. hope that helps.

[Hondady]

Go with the 15's. You can't go wrong with them.

[Chikubi]

There was an article I read not to long ago that basically said that every pound of unsprung weight equates to apx. 10 lbs overall weight of the car -- i.e. if you cut 3 pounds of weight on your wheels, tires, rotors, etc. then it's like lightening the car 30 pounds, and the reverse is true as well. In my case, I was looking at some forged 16" SSR's that were like 11 pounds each and tires for them were 20, so one wheel tire combo was 31 pounds -- about 4 pounds lighter than stock 15's w/ tires. 4lbs x 4 wheels = 16 lbs unsprung weight, so about 160 lbs of overall weight savings. You'd have to tear quite a bit of crap off the car to save 160 lbs normally, so it's a pretty impressive gain.

[Gil554]

Chikubi- If you can find the article or a link, it would be sweet! I could feel a dramatic difference in autox, but not much for the street with a previous car. If weight savings are that significant, they'll be about first on my list! This may be especially true for the Fit because of it's light weight (seeing as many other cars hover around 3000#).

G

[Chikubi]

It was " Why wheels are more than just tire holders", pgs. 111-114 in the 12/06 Modified. It's not the most detailed article by any means, but that factoid stuck in my head.

[Gil554]

Chikubi- Thanks for pointing me in the right direction! I like to go back and read the articles even if if just for the factoid. It also helps for "nuh unh...ya hunh" arguments in forums.

G

[YeeFit]

Thanks for all the info everyone! I think I have made my decision to go with a lightweight 15" combo over the 17"s.... the 17's are wicked nice, but in the end I still think 15's can look great on our cars and I'll gain the performance/mileage outta the lighter wheels.

[aznguyen316]

Originally Posted by Chikubi

There was an article I read not to long ago that basically said that every pound of unsprung weight equates to apx. 10 lbs overall weight of the car -- i.e. if you cut 3 pounds of weight on your wheels, tires, rotors, etc. then it's like lightening the car 30 pounds, and the reverse is true as well. In my case, I was looking at some forged 16" SSR's that were like 11 pounds each and tires for them were 20, so one wheel tire combo was 31 pounds -- about 4 pounds lighter than stock 15's w/ tires. 4lbs x 4 wheels = 16 lbs unsprung weight, so about 160 lbs of overall weight savings. You'd have to tear quite a bit of crap off the car to save 160 lbs normally, so it's a pretty impressive gain.

that is very interesting. I'm sure further studies can be done on this, but I like that thought. Maybe lightweight lugs aren't just bogus lol.. My 16's fortunately are lighter than the oem 15s so I'm happy.

[mahout]

Yes. The less rotating mass (weight) the easier it is for the engine to accelerate (and brake) so its worthwhile in drag racing or in road racing.